In the context of radio access technologies (RATs) and, in particular, those that implement multiple-input multiple-output (MIMO) antenna technologies, linear beamforming or pre-coding is prevalently employed to improve a received signal-to-noise ratio (SNR) and further suppress interference. In order to accomplish this, pre-coding requires knowledge of downlink channel state information (CSI) at the transmit side (e.g. at the base station). In some frequency division duplex (FDD) systems, such downlink CSI is obtained from a wireless device through uplink feedback.
In some FDD systems like those that implement long term evolution (LTE) standards-based protocols, an implicit quantized CSI feedback is used. However, use of such quantized CSI feedback is accompanied by channel quantization error. This error, in turn, results in performance degradation at the pre-coding stage, since, by virtue of the foregoing error, the CSI feedback does not accurately reflect channel conditions.